Dead latching mechanism



Ju 7, 1953 s e. HAGSTROM 2,544,705

DEAD LATCHING MECHANISM Filed Nov. 15, 1950 z Sheets-Sheet 1 ATTORNEYS? Patented July 7, 1953 7 2,644,705 r "DEAD LATCI -IING MECHANISM Gotthard Hagstrom, Greenwich, Conn., assignor to The Safe Padlock and Hardware Company, Lancaster, Pa., a corporation of Pennsylvania Application November 15, 1950, Serial No. 195,824

' Myinvention relates to certain improvements in deadlatching mechanisms; and the naturefand objects of the invention will be readily recognized by those skilled in the arts to which it relates in the light of the following explanation and detailed description of the accompanying drawings illustrating what I now believe to be the preferred embodiment or mechanical expression of the invention from among various other forms, arrangements, designs, embodiments, modifications, variations; combinations and constructions, of which the invention is capable within the broad spirit and scope thereof as defined by the appended claims.

The invention is directed more specifically'to those types of dead latching mechanisms'which utilize a so-called dead latch or auxiliary bolt member in cooperation with the main latch bolt of a door latching mechanism. In'such types of dead latching mechanisms, the auxiliary or dead latch bolt member is so mounted and arranged that upon closing of a door with the main latch bolt projected into its keeper, the dead latch bolt is depressed by engagement with the strike plate and thereby actuates a dogging member into position dogging and locking the main latch bolt against forceful depression to a position cleared from the keeper and unlatching the door. Such dead latching mechanisms as now generally available are usually characterized by the fact that Whenever the door which mounts such mechanism 5 is in closed position with the dead latch bolt depressed by engagement with the strike plate, the dead latching dog member is also actuated to dogging position. When it is realizedthat a'door latch mechanism after installation ona door may never be subjected throughout its installed life to any attempts to forcefully retract the latch bolt, it follows that the continual actuation of the dead latching dog to dogging position each" time that the door is closed is a'totally unnecessary and completely inefiicient operation. Such continual dead latching dog actuation tends 'to wear outthe mechanism and reduce the effective life thereof, as well as calling for complication of mechanism for effecting such continualdogging.

12 Claims. (Cl.-292169) It'is, therefore, a primary object of my invention to provide a deadlatching mechanism in which the dead latching dog member thereof is never actuated to dogging position unless and until an attempt is made to force the main latch boltof the door latch mechanism from latching position in its keeper with the door closed.

Another object is to provide a dead latching .mechanism in which the mechanism is conditioned and set up for operation of tl edeadlatching dog member to dogging position whenever a door is in closed position but in which the dog is never actuated to dogging position from its normal, undogged position unless an attempt is made to force the latch bolt from door latching posi-- tion in'its keeper. 7

Another object is to provide a dead latching mechanism of a type utilizing a strike engaged and actuated dead latch or-auxiliary bolt, in which mechanism such auxiliary bolt performsno function in the actual operation of the dead latching dog between dogging and non-dogging positions,

but merely serves to condition dog engageable structure for engagement by the dog when the latter isactuated to dogging position. 1

A further object is to utilize the .main latch bolt retracting member of thelatch mechanism to actuate the dead latching dog from dogging position to itsynormal, non-dogging position upon release from the main latch bolt of depressive forces that may be applied to the tip thereof when V the door is in closedposition with in its keeper. 1 SA further object is to provide such a mechanism in which :the biasing spring of the latch bolt mechanism for projecting the latch bolt, is utilized to biasthe dead latching dog to dogging position. A further object is to provide a design of such a mechanism in which the dead latching dog is mounted onv the tail-piece of the main latch bolt of the latching mechanism. A'further object is toprovide a dead latching the latch .bolt

-mechanism of the dead latch bolt'type which' is of extreme mechanical simplicity with a minimum of parts capable of low cost manufacture and which can'be readily assembled with the latch o t mec n m. 1 I

' Withthe foregoing and various other objects, features and results in view which will be readily recognized from the following detailed description and explanation, my invention consists in certain novel features in design and constructionof parts I and elements, and in combinations andsubcom inations thereof, all as will be more fully referred .to and specified hereinafter. Referring to the accompanying drawings, in which similar reference characters refer to corresponding .parts throughout the several. figures he e f r I V Fig-[,1 is a view in horizontal section through the free edgeportion of a door and showing in topplana knob operated latch bolt unit incorpovrating a dead'latching mechanism invention. [1-

Fig. 2 is'a viewin vertical longitudinal section I I of. m'y'fpresent il w llflal n t of mg. 1, taken as 'on the line 22 of Fig. 1, and showing the dead latching dog in the non-dogging position thereof assumed with the door open and both the latch bolt and dead latch bolt in projected positions.

Fig. 3 is a view in transverse, vertical section through the latch bolt unit of Fig. 1, taken a on tuatin yoke, the roll back and the knob spindle,"

having been broken away and removed.

Fig. 6 is an exploded view showing in perspective and in separated relation, the several parts and components making up the latch bolt unit and dead latching mechanism of Figs. 1 to 5.

Fig. '7 is a view similar to Fig. 2, but showing the dead latch bolt in retracted position with the dead latching dog conditioned for dogging operation upon depression of the latch bolt.

Fig. 8 is a view similar to Figs. 2 and 7, but

showing the dead latching dog in latched or locked position as a result of depression of the latch bolt when the dead or auxiliary bolt is in depressed position. 7

Fi 9 is a view in horizontal, longitudinal section through the latch bolt unit of Fig. 1, showing the latch bolt in door latching position in the keeper and the auxiliary bolt depressed by engagement with the strike plate when the door is closed.

A latch bolt unit of thedoor knob operated type, and embodying one possible exemplification of dead latching mechanism of my invention, is disclosed herein by way of example, in a form primarily designedand intended for use with a so-called outside door in which the latch bolt is adapted to be locked against retraction by suit-.-

able key controlled locking means when the door on which the unit is mounted isclosed. The dead latching mechanism is not, however, in any sense restricted or limited to embodiment in or adaptation to either door knob actuated latch bolt mech: anisms or to use with latch bolt units on outside doors. Latch bolt units of the illustrated example may be used on inside doors or for any desired type of closure, and in addition, the principles and features presented to the art by the invention may be expressed mechanically and structurally in various other forms and adaptations than that of the specific embodiment. thereof of this example.

In the example embodiment, a tubular latch bolt unit'L is utilized of a type embodying the inventions as disclosed and claimed in my patent application Serial No. 178,-

pending U. S. i 897, entitled Door Latch Mechanism. This unit L basically embodies an elongated, rectangular case C comprised of a body ID stamped or formed in any suitable manner from sheet material to provide a vertical side wall Illa, top wall Illb, bottom wall Hi0 and an open side closed by a suitable cap or cover plate II. The case C is, closed Roll-back i5 is provided with a rectangular opencover plate II are formed with'openings l6a,

therethrough in axial alignment with roll back opening It and hub opening I5b, for receiving therethrough the rotatable latch bolt actuating [spindle 3 (see Figs. 1 and 2), in the general manat its inner end by an end wall ltd formed on body II), and is open at its forward end atwhich there is secured a vertically disposed, rectangular, composite face plate structure I l. The case.

C mounts therein a roll-back I5 for rotation about a horizontal axis disposed transversely of the case, the roll-back I5 being rotatably mounted on v a suitable bearing forming hub member l5a secured in vertically disposed position in the case.

ner familiar in this art.

The vertically disposed side wall Illa of case body Ill is formed with a laterally, outwardly projected or offset side wall portion I8 which is disposed longitudinally thereof and which extends from, and opens through the forward open end of the case 0, to a location adjacent but spaced forwardly from opening IBa in case body wall Ill. At its inner end the auxiliary bolt housing I8 is closed by an end wall [8a which joins and merges with wall Illa and the housing side wall I8. The wall portion is transversely curved to form a concave channel at its inner side with the contour at its outer side being convex. This outwardly offset wall portion It forms both a housing and a slide and guideway of U-shape cross section, for slidably receiving therein an auxil-' iary or dead latch bolt D, as will be referred to.

At its rear end between hub bearing member l5ct and the inner end wall [0d of case C, the yoke member 20 is bent inwardly for its full width to form the vertically disposed flange 22 thereacross which has at its free edge, slidable bearing engagement with the inner surface of case side wall Illa. Yoke member 20 at the forward upper side of wall 2I, has an. inwardly bent, horizontally disposed finger or lug 23, which lug has slidable bearing engagement at its free end with the inner side of case wall Illa. At its forward, lower side yoke'member 20 is formed with an inturn'ed flange portion 24 which is vertically disposed and located in a vertical plane 'passingthrough the rear edge of the horizontally disposed lug 23 thereabove. The inner free end of flange 24 has slidable bearing engagement with the inner side of case wall. Illa, and the flange is-formed with a rectangular opening 25 therethrough at the outer side portion thereof, with such opening being extended a. slight 'distance rearwardly into the yoke body wall 2|. Yoke member 20' thus bridges roll-back I5 and hubmember Isa, with the rear flange 22 and forward flange providing'the positioning and bearing supports for reciprocation of the yoke member within the case C. Yoke member, 20 has lateral guiding support in the direction out;- wardly toward cover plate I l by slidable. engagement with the inner side, flat surfaces provided bysuch cover plate. 7 V r The yoke member 20 has bent upwardly therefrom at the upper and lower side edges of body wall 2 l; the upwardly and downwardly projected ears- 20a, respectively. Ears 20a are located 'on wallr2[intermediate the elongated opening 21a and 'in positions at the rear of end engaged by the .upperfand lower lugs or cams l1, respec tively, of the roll back [.5 (see Fig. 2).; .Hence, in assembled position, rotation of the roll-back I5 in either direction will cause the rearwardly moving lug H to engage its yoke mounted ear 20a to thereby force or slide the yoke rearwardly in case for latchbolt retraction.

The latch bolt B of the latch unit L, may be considered to be of generally conventional design to provide the usual inclined face or surface for slidably engaging against the strike plate 2 of a door frame. In this instance, latch bolt B is slidably positioned in and guided by a rectangular opening Ma formed through face plate '14 in alignment with the forward, open end of case C. The latch bolt B has suitably connected to the rear end thereof, a tail-piece 30 which extends inwardly a' distance and through the case C, and which is provided at its inner end with an upwardly projected nose forming a yoke engaging hook 3!. In this example, the tailpiece 30 is of rectangular cross section (see Fig. 4). The hooked inner end 3| of tail-piece 36 extends in assembled position into the rectangular opening 25 of the forward flange 24 of yoke member 20, in a position with the upwardly extended nose member of the hook 3| engagable against the inner side edge portion 24a at the upper side of opening 25. Thus, upon rearward movement of yoke 20 the hooked inner end 31 of the tail-piece 30 being engaged with yoke member 20 at 24.01 will draw the tail-piece rearwardly to retract the latch bolt B. But, latch bolt B with tail-piece 30 is movable rearwardly relative to and independently of yoke member 20 by rearwardly acting forces applied to the latch bolt at the forward, outer end thereof. Under such conditions tail-piece 3.0 slides freely rearwardly through yoke member opening 25 completely independently of the yoke member.

A coil expansion spring 32 is mounted on and over tail-piece 3| under compression between the rear side of ;the latch bolt B and flange 24 of yoke member. 20. Hence, the latch bolt B when depressed or moved inwardly .relative to yoke member 20 places spring 32 under an increased degree of compression, so that, upon release of the inwardly acting forces on the latch bolt the latter is instantlyprojected outwardly to normal, strike engaging, door-latching position (see Fig. 2).

' Yoke member 20 is spring loaded and normally continuously biased to its forwardly projected position, as shown in Fig. 2. 7 The spring loading is effected, in the example embodiment, by a coil expansion spring'33 which is inserted under compression within case C between the inner end wall Ind of the case and the inner end flange 22 of yoke member 20. When the roll-back I ,is

rotated in either direction, yoke member 20 'is forced rearwardly against and compresses spring 33 'an'd'the latch bolt B is retracted. Upon release of the turning forces on roll-back I 5, spring 33 acts to instantly move the yoke member 20 forwardly to normal, latch bolt projected posi-. tion. It is important to note that when latch bolt Bis retracted by rearward movement of qke-mem r 2 s n t r s 3 the sp i 3 on the yoke by, the spring 32.,

. 6 is not further compressed as under .these conditions latch bolt B and tail-piece 30 do not have movement relative to yoke member .20, sothat, the spacing between yoke member flange 24 and the rear .or inner side "oflatch boltB does not change but r'emainsconstant. However, when latch boltB is depressed and retracted. independently of yoke member 20, the spring 321s further compressed. In order'to permit of such compression, spring.,332must not yield to the forcesappliedto yoke member 211 by. spring; 32, hence, spring 33 is formed heavier so as to exert a force greater than the; maximum force. exerted The foregoing conditions are utilized by my present invention is eifecting the dogging or locking of the;latch bolt B, in a manner to be referred to hereinafter.

By my invention I provide for dead latching, that is, looking the latch bolt B against depression to a sufiicientdegree when in door latched position in the keeper of the strike plate 12,; to

perm-it of the bolt beingdisengaged from, the keeper inorder to open the-door. dead latching of the latch bolt unit L of theex-v ample embodiment, by the addition to the latc mechanism of unit'L, of only two major elements orcomponents, namely, a deadlatching dog: 50 andthe dead lat-ch orauxiliary bo1t,D. I utilize elements. of the latch bolt mechanism ofunit L for mounting and for the operative functioning of the dead latching dog 50 without requiring the addition of other elements or mechanism, I

utilize the case 0 of the unit Liar-dogging en--,-

gagement-bythe dog 50, thus eliminating the {necessity for additionalstructure for this purpose. And I utilize the dead latch or --auxiliary bolt D for the purpose solely of conditioning-or 'making accessible to the dog 50,,the dog engaged portion of case C, so that, bolt D performs no dog actuating functions and thus becomes an unloaded member, except for ,its depression: by engagement with the strike plate. 2 and its pro-- ection by a light biasing spring;associatedpthere:

The dead latching dog 50, referringtQFig-G in p-articular comprises a generally L-shaped member having the vertically disposed mounting leg :5! and the generally horizontally'disposed dogging, arm 52. I The outer end-lengthof arm 52 is formed of a cam portion 53 which'extends upwardly from arm 52 at. an angle of "approxi mately 45 thereto. Atthe outer end ofcamportion 53, the arm terminates in a vertically upwardlyextended dogging lug 54 whichis of reduced,- width relative to thewidth of the arm to provide at one side of the lug a horizontally andtransversely disposed shoulder 54a. V I- The dead latching dog member 50, referring now to Figs. 2, 4, 7 and 8 in particular, is..in accordance with my invention, mounted onthe tail-piece 30 of the latch bolt 3- by extending tail-piece3iithrough the rectangular opening 5k; in the mounting leg 5| of the dog, with such mounting legbeing positioned at the forwardend of the tail-piece between the; forward'end of spring 32 and the rear side of bolt B. The dogill is thus positioned and mounted on tails-piece 3!]v with the mounting leg 5] extended vertically upwardly therefrom and the dogging arm 52 extending generally horizontally and rearwardly through the case over andabove spring 32, and

horizontally ,disposed forward finger or lug 23:01

I effect this.

7 yoke 20-, between that leg and the hpp'er' 'edge. surface of the forward flange 24 of the yoke. Iii-such position the'dogging lug '54 of dog 50 extends upwardly into a. non-dogging position, as rshownlin Fig. 2, with its upper edge lying immediately adjacent but slightly below the under surf ace of the top wall lEib of case C and with its rear vertical surface engaged against "the rear edge surface 23aof lug 23 of yoke 20.

Thus mounted, due to the verticallyel'ongated opening la. in' mounting leg 5|, the dogging member 5a has-'limitedirocking movement-on tailpieceS O to swing arm 52 upwardly and downwardly and thus raise and lower lug '54 toward and from case top wall Iflb. As the mounting leg 5l' is spring loaded and continually biased forwardly toward latch bolt B by spring 32, it follows that if the free end of arm 52 is unconstrained then the spring 32 will maintain arm 5| in forwardly rocked position against the rear side of latch bolt B with the arm 52 and dogging lug 5 being in their maximum upwardly swung posi- QSuch position, whichis the dogging positionofdo'g 50, is shown in Fig. 8.

With the latch bolt mechanism of unit L in its norm'alposition with the latch bolt B fully projected, the dog member 55 is rocked downwardly and rearwardly' on tail-piece 30 against the force of spring: 32 by the camming engagement of leg 2'3- o'f yol e"2:fi with the upper camming surface 53o t the cam portion 53 of dog arm 52. This position is shown in Fig, 2, with the dogging lug 54 in its non-dogging, lowered position at the underside of top wall lb and engaged at its forward's'ide with the rear edge portion 23a of the fingerbr lug 23. r

The u-pper'wall lllb of case C is utilized to provide structure engaged by the dogging lug 54 of dog 5ll, when the dog is actuated to move dogging 111g 54- upwardly to its dogging position. In this example, a hole or opening 55, preferably rectangular-as shown, is provided in and through top 'wall Nb of case C in position abov'ean'd for receiving therein the dogging lug 5; of dog 50. The topwall Nib forms across the rear side of thisbpening 55, a contact or abutment edge 55a. for-dogging engagement by lug 54 of dog 50'when the dog is actuated to dogging position. Thus,

' when'the latch bo'lt'B is depressed by inwardly acting forces applied to the outer end thereof, tail-piece =30 of the latch bolt is displaced rearwardly-' relative to and independently of yoke member '20, and the'dead latching dog 50 is also moved irearwardly with the tail-piece and bolt B; This rearward movement displaces the camming portion 53aand dogging lug 54 of arm 52 rearwardly, so that, under the action of the forces of spring 3 2,'-the dog 50 is rocked forwardly and the doggi-ng'lug 54 is projected upwardly into the opening 55. Continued depression of latch bolt B and rearward movement of tail-piece 30'and dog 55 'issto'pped by engagement of the rear 'side of -lug -5'4"with'the abutment edge 55a across the rear side of opening 55. Thus, the latch'bolt B is dogged and locked against further depression. The "design and relative positioning of the several elements and components effected by and participating in this dogging'action, is such that from its normal projected position, latch'bolt B is permittedbut relatively slight inward depression before dogging is effected by engagement of the dogging lug 54 with the abutment edge 550. provided by case wall l'ilb. Upon release of the depressive:forces-acting'onlatch bolt B,spring'3'2 acts to return bolt B to its normal projected position, and by so doing dogging member 50 is thereby moved forwardly, so that, the camming surface 530. of camming portion 153 of dog arm 52 engages with the rear edge portion of arm .23 of yoke 20, and is thereby cammed downwardly to displace lug-54 from opening 55, to the non dogging position as shown in Fig. 2. v

.In this instance, the width of the hole oraopening..55 in the 'case'side-wall lllb is but slightly greater than the dogging lug 54.0f dog 50 which is to. bepreceive'd therein. Thus, when the dog 50 is rocked upwardly to position with'the do ging 111g 54 received in opening 55, the shoulder 54a of the dog may serve as a limiting stop by 'slidable engagement with the under surface of wall lllb.

The dead latch or auxiliary bolt D, referring now to Figs. 3, 4 and 6 in particular, may be formed or pressed-up from relatively thin gauge sheet material, such as sheet brass. The, bolt D is comprised of a, main body 60 of U orchannel shape in cross section, having a transversely curved or convex outer side surface complementary to the concavev inner side surface of the channel or slideway formed by the housing [B of case C. The bolt D has a length less than the slideway formed by housing l8 and is freely slidably mounted and received in suchhousing for reciprocation longitudinal-1y therein. The face plate M of the latch unit L is formed with an opening .Mb therethrough as a lateral extension of the latch bolt receiving opening Ma, with th yopening Mb aligned with the .open forward end of the slideway formed by housing I8. The auxiliarybolt D in mounted position may thus reciprocally extend forwardly through opening Mb to a position projected outwardly beyondface plate M.

The main U-section body member 60 of auxiliary bolt D has for a distance along its upper side wall, an upwardly projected ide flange 6| located along "the inner edge of the upper side wall and being adapted to slidably engage over the adjacent inner side surface of case sidewall Illa along the upper side of 'the channel formed by housing 1'8. Intermediate its ends, bolt body 60 is provided at the inner side thereof with a laterally offset side wall 52 which extends across the channel formed therein. At its'forward end the wal1'62 has an inturned flange portion 63 extended into the channel of body 69, toformwith wall 52a a forwardly closed housing for a light biasing spring 54. The outer side wall of "body 6!) is formed with an opening 60a therethrough (see Figs. 3 and 5). .Alug. 64a is bent up'from side-wall [8a ofhousing 1-8 and projects inwardly therefrom. e

I When dead-latch bolt D is in mounted, assembledposition in the-guideway of case 0 formed by housing 18, the lug 64a extends inwardly through side opening 50a of body .50 of the bolt and 'thebiasing spring'B l is confined within the housing provided bywall 62 under compression between lug 64a engaged by the rear end of the spring and end wall 63 engaged by the forward end of the spring. In such assembled position the forward length of bolt Dprojects outwardly through opening Nb of face plate [4 for a distance substantially equal to the distance of normal projection of the main latch bolt B, as will be clear by reference to Figs. 1 and 5. The outer end-of the bolt D may be closed by asuitable end wall 65 which provides an abutting surface for engagement with' the strike plate 2. The inner side of the latch bolt Dis *f-ormedwith' a'shoulder 56 thereacross which, with the bolts B and D in latch or auxiliary bolt D, due to the engagement of shoulder 66 against wall 63, will be retracted as a unit with bolt B. v

The sole purpose of the auxiliary bolt D is to condition, that is to open or to block-off, the opening 55 of case wall lllb which is adapted to receive therein the dogging lug 54 of dog 50. To this end, I provide bolt D at its inner rear end portion and on the upper side thereof, with a horizontally disposed plate or cover member which is positioned on bolt D, so that when the bolt is in forwardly proj cted position, the plate H1 is located below and closes or blocks off opening 55 against the entry thereinto of the dogging lug 54. pressed and forced inwardly a sufiicient distance, the plate In is moved rearwardly to a position removed from position blocking opening 55 and thus conditioning that opening for upward movement thereinto of the dogging lug 54 of dog 50. Such position is shown in Fig. 7.

A latch bolt unit L incorporating the dead latching mechanism of my invention, is shown in Fig. l, in mounted and installed position in a door A. The latch bolt unit L is mounted in the usual manner in the door A with the face plate l4.thereof attached at the outer free edge of the door and with the main latch bolt B and auxiliary bolt D reciprocal to and from normal, projected positions through the face' plate. A usual squared spindle S extends through the door and the square opening I6 in the roll-back l5, so that rotation of the'spindle in either direction will efi'ect retraction of latch bolt B and the auxiliary bolt D as a unit. The ends of spindle S at opposite sides of the door A mount the usual inner knob I and outer knob 0. Any suitable key controlled locking means not shown may be provided for locking the spindle S against rotation by outer knob O, in a manner familiar in the art.

The unit L is shown in Figs. 1, 2 and 5, in the normal projected positions assumed by bolts B and D when the door A is in an open position. When the door is in closed position, either locked or unlocked, the latch bolt B, referring now to Figs. '7. 8, and 9, is projected into the keeper formed in the strike plate 2 in the usual manner to; latch thedoor against opening. The dead latch or auxiliary bolt D, however, is engaged atits outer end with th strike plate 2 as' the door is closed and is depressed thereby to the position shown when the door reaches its closed 3 When, however, auxiliary bolt D is demay be effected without releasing dog for upward swinging to dogging position. This is so because rearward movement of yoke member 20 by the action of spindle S will retract latch bolt B. without changing the relative positions of the yoke member and the latch bolt.

With the mechanism in the door closed and latched position of Fig. 7, if an attempt is made to forcefully depress latch bolt B from its position in its keeper inrstrike 2, as by inserting a knife or thin blade between the strike and face plate M, the bolt B with tail-piece 30 will be moved inwardly relative to and independently of yoke member 29 which will thus move dead latching dog 50 rearwardly to aposition-unconstrained by the yoke lug 23, so that, spring 32 acts in stantly to rock dog 50 forwardly and upwardly and thereby project dogging lug 54 into opening 55. Further depression of latch bolt B will then be prevented by engagement of lug 54 with surface a of wall I01), and the bolt will be effec tively locked against further depression anddisplacement from its keeper. In such operation with the door closed, plate 10 has been moved by the depressed, auxiliary bolt Dv to a position clearing opening 55 for entry thereinto of the dogging lug 54. 1

Thus, the dead latching mechanism of my invention under all normal conditions is never actuated to dogging position until an attempt is made to depress latch bolt B from its door latching position in its keeper in the strike 2. a

Attention is directed to the fact that .if end pressure is applied to the latch bolt B when the door is shut, or the friction against the latch by thestrike 2 is so great as to prevent the latch bolt from extending fully into the strike, or suflicient clearancein the material of the door behind th strike plate 2 has not been provided, it may be possible that the dead latching dog 50 will be actuated to swing the dogging lug 54 into the opening 55 of case side wall Iflb. Under these conditions the dogging lug 54 might remain in dogging position in the opening 55. However, rotation of the spindle S by one of the knobs mounted thereon will cause the yoke member 20 to move and the lug 23 carried by the yoke member will then slide onto the camming surface 53a and cause dog 50 to'be rocked downwardly out of dogging position, thus permitting the latch bolt B to be withdrawn. The movement of the yoke member 20 caused by rotation. of spindle S position. Depression and rearward displacement of auxiliary bolt D moves plate 10 thereof to a position to the rear and clearing dogging open- 1 ing 55 in the top wall lb of case 0, as shown clearly. by Fig. 7. In this manner, the opening 55 is conditioned for dogging action of the dog 50. In the position of Fig. 7, with latch bolt B projected the lug 23 of the yoke member '20 constrains dog 50 to its rearwardly and downwardly rocked position against the force of spring 32, so that, the dogging lug 54 is located below and clear of top wall Nib and the opening 55 therein. In such position it will be obvious that normal latch bolt retraction by rotation of spindle S will always result in retraction of latch bolt B regardless of the position of the dead latching dog 50.

With the door A in open position, both the latch boltB and the auxiliary bolt D are in their fully projected positions, as shown in Fig. 1. When the door A is swung to closed, latched position, the latch bolt'B is in the usual manner by engagement with the strike 2, depressed asit moves across the strike to closed position until it is aligned with and projects into'the keeper provided by the strike. As latch bolt' B is depressed it also depresses auxiliary boltDf The depression of latch bolt B is independent of yoke member 20, andmay eifect dogging operation of dog 56 in a manner hereinbefore explained. However, as will be noted from Fig. 2, when both bolts B and D are projecteolthe dog blocking plate!!! of auxiliary bolt Dis over dogging lug 54, that is, is between that lug and case wall [0b. As bolts .B and D are simultaneously depressed, it follows that the blockingrelationship of plate 10 to dog- 1 1' 'anyrdogging action of dead latching dog 50 is rendered ineffective. As soon as the latch bolt B in the door closing operation is aligned with the keeper in the'strike 2, it projects into that keeper so that dog 5% assumes non-dogging position under the action of lug 23, while the auxiliary bolt D remains depressed by engagement with the strike plate '2. The blocking plate of bolt D thus remains positioned removed from opening 55', so that dogging action may thereafter take place if an attempt is made to depress latch bolt 13 fromthe keeper, 7 V It will also be evident to those skilled in the art, that various changes, modifications, substitutions, eliminations and additions may be resorted to without departing from the broad spirit and Scope of my invention, and, hence, it is not my intention to limit the invention in all respects to the exact and specific disclosures of the example embodiment herein illustrated and described, except as may be required by clearly intended specific limitations thereto included in any of the appended claims. r

What I claim is:

1. In a latch bolt mechanism, in combination, a case; a latch bolt including, a tail-piece mounted in said case for reciprocation to and from a projected, latching position; means for retracting said latch bolt including, a yoke member reciprocally mounted insaid case and being en'- gageable with said latch bolt tail-piece to retract said latch bolt from said projected position; said latch bolt and tail-piece being depressible from said projected position independently of said yoke member; a coil expansion spring mounted on said tail-piece under compression between said latch bolt and the adjacent end of said yoke member and being adapted to continuously bias said latch bolt to its projected position; a dogging member comprising a leg mounted on said tail-piece between said latch bolt and said spring in position extendedradially from and being rockable on said tail-piece in directions axiallythereof, a dogging arm extended laterally from said leg inwardly and axially of said tail-piece, and a dogging lug at the free end of said arm extended laterally outwardly therefrom toward said case; said dogging member being rockable on said tail-piece to move said dogging lug outwardly to a dogging position and inwardly to a non-dogging position; said spring acting to continuously bias said dogging member to dogging position; said case being formed to provide a fixed abutment to be engaged by said dogging lug in dogging position thereof; and means on said yoke member adapted to; be

engaged by said dogging member to'constrain' said member to non-dogging positions when 'said latch bolt is in projected position.

2. In a latch bolt mechanism, in combination; a case; a latch bolt mounted in said case for reciprocation to andfrom a latching position projected from the case; a spring unit adapted to continuously bias said latch bolt to said projected position; mechanism for retracting said latch bolt from its said projected position; said latch bolt being depressible from projected position independently of said retracting mechanism; a dogging member mounted on said latch bolt for movements thereon between a dogging position locking said latch bolt against depression from said projected, latching'position independently of said retracting mechanism and a nondogging position releasing said latch bolt for depression; said biasing spring unit being con:- nected with said dogging member and adapted 12 to act to continuouslybias said dogging member from non-dogging position to' dogging" posi' tion; a constraining member positioned to 'be releasably engaged by said dogging member in projected position of said latch bolt to con"- strain said dogging member in non-dogging pOSlT- tion; and said dogging member being adapted'to be engaged with and moved by said latch bolt to position released from said constraining member for biasing by said spring unit to dogging position when said latch bolt is depressed from its said projected position'independently of said retracting mechanism.

3. In a latch bolt mechanism, in combination; a case; a fixed abutment on said case; a latch bolt mounted in said case for movements to and from a latching position projected from the case; spring means connected with and adapted to continuously bias said latch bolt to said projected position; mechanism for retracting said latch'bolt from its said projected position; said latch bolt being depressible from projected position against the action of said spring means independently of said retracting mechanism; a dogging member mounted on said latch bolt for movements thereon between a dogging position engaged with said abutment to lock said latch bolt against depression' from its said projected position and a nondogging position disengaged from said abutment to release said latch bolt for retraction; said latch bolt biasing spring means being also connected with said dogging member and being adapted to act to continuously bias said dogging member from non-dogging to dogging position on said latch bolt; said retracting mechanism including a constraining member mounted in position thereon adapted to be releasably engaged by and to constrain said dogging member in its non-dogging position in projected position of said latch bolt by said spring means and in all retracted positions of said latch bolt by said retracting mechanism; and said dogging member being adapted to be engaged by and moved to position disengaged from said constraining member for biasing by said spring means to dogging position by movement of said latch bolt from its said projected, latching'position independentlyof said retracting mechanism. v- I v 4. In a latch bolt mechanism, in combination; a case; a latch bolt mounted in said case for reciprocation to and from a door latching position projected from the case; spring means adapted to continuously bias said latch bolt to said projected position; retracting mechanism engageable With said latch bolt for retracting the latchbolt from projected position; said latch bolt being depressible from projectedposition independently. of said retracting mechanism; an abutment on said case; a dogging member mounted on said latch bolt formovements thereon between ,a dogging position engaged with said abutment to lock'said latch bolt against depression. from its said projected position independently of said retracting mechanism and a. non-dogging position disengaged from, said abutment to release said latch bolt for retraction; a blocking member mounted in said case for movements between a position blocking said abutment from engagement by said dogging member and position unblocking said abutment; an auxiliarybolt reciprocally mounted in said case for movements to and from position projected from the case, said I auxiliary bolt being adapted to be depressed from projected position by engagement with a strike plate; said blocking member being 7 13 connected with and actuated by said auxiliary bolt to block said abutment with the auxiliary bolt in projected position and to unlock the abutment with the auxiliary bolt depressed; a constraining member on said retracting mechanism adapted to be releasably engaged by said dogging member to constrain the dogging member to nondogging position with said latch bolt in projected and retracted positions; and said dogging member being mounted on said latch bolt for movement bodily therewith to position released from said constraining member when said latch bolt is depressed from its said projected, latching position independently of said retracting mech-- anism. I

5. In a latch bolt mechanism, in combination, a case; a latch bolt mounted in said case for reciprocation to and from a latching position projected from the case; spring means adapted to continuously bias said latch bolt to said projecrted position; retracting mechanism engageable with said latch bolt for retracting said bolt from said projected position to retracted positions; said latch bolt being depressible from said projected position independently of said retracting mechanism; an abutment on said case; a dogging member mounted on said latch bolt for movements thereon between a dogging position engaged with said abutment to lock said latch bolt against independent depression from its said projected position to retracted position and a non-dogging position disengaged from said abutment to release said latch bolt for retraction by said retracting mechanism; means adapted to be engaged by and to constrain said dogging member to non-dogging position with said latch bolt in its said projected position; and said dogging member being mounted on said latch bolt for movement thereby from position engaged with to position disengaged from said constraining means for movement thereof to dogging position solely by initial movement of said latch upon depression thereof from its said projected position independently of said retracting mechanism.

6. In latch bolt mechanism, in combination, ,a case; a latch bolt mounted in said case for reciprocation to and from a latching position projected from the case; means for retracting said latch bolt from said projected position; said latch bolt being depressibl from said projected position independently of said retracting means; an abutment on said case; a dogging member mounted on said latch bolt for movements between a dogging position engaged with said abutment when said latch bolt is in said projected position to lock said bolt against depression and a non-dogging position disengaged from said abutment; biasing means being connected with said dogging member adapted to bias said dogging member from non-dogging to dogging position; an auxiliary bolt reciprocally mounted in said case for movements to and from a position projected from and a position depressed into said case; said auxiliary bolt being provided with a blocking member movable therewith and positioned thereon to be interposed between said abutment and said dogging member with said auxiliary bolt in projected positions; and said blocking member being adapted to be moved by said auxiliary bolt to position removed from between said dogging member and said abutment with said auxiliary bolt in depressed position.

7. In a latch bolt mechanism, incombination, a case; a latch bolt mounted in said case said case for movements between a dogging position engaged with said abutment surface tolock said latch bolt against depression'from projected to retracted, unlatched position and a non-dogging position "disengaged from saidabutment surface for retraction of said latch bolt; an auxiliary bolt mounted in said case for'movements between a position projected therefromand aposition depressed thereinto; and said auxiliary bolt being formed to provide a block-' ing portion adapted to be positioned by saidauxiliary bolt when in projected position to' block off said abutment surface from engagement by said dogging member and when said auxil iary bolt is in depressed position to be positionedthereby to clear and unblock said abutment surface for engagement by saiddogging member.

8. In a latch bolt mechanism, in combination; a case; a latch bolt mounted in said casejfor reciprocation between projected position and retracted position; an auxiliary bolt mounted said case for reciprocation between projected position and retracted position, said auxiliary bolt being mounted for depression from projected to retracted position independently of said men; bolt; means for retracting said latch bolt from projected position; means adapted to continu ously bias said auxiliary bolt to projected posi tion; said latch bolt being depressible from ro: jected position independently of said retracting means; a fixed abutment on said case; a dogging 7 member mounted on said latch bolt'for movements thereby between a dogging position en-" gaged with said fixed abutment and a non-dogging position; disengaged from said abutment; means connected with said dogging member adapted to continuously bias said member from non-dogging position to dogging position; a constraining member mounted on said retracting means adapted to be located thereby in position to'constrain said dogging memberto non-dog' gin g position with said latch bolt in projected position; said dogging member being adapted to be moved by said latch bolt to position released from said constraining member by depression ofsaid latch bolt; and a blocking member onsaid auxiliary bolt adapted to be positioned by the ,latter to block said dogging member from engagement with said fixed abutment when said auxiliary 'bolt is in projected position and toiclear said dogging member for engagement with said fixed abutment when said auxiliary bolt is depressed from its projected position. I f

9. In combination, a case; a latch bolt mounted in said case for reciprocation between projected position and retracted position; means including a yoke member reciprocally mounted in said case for retracting said latch bolt from its pro- I jected position; spring means interposed between said latch bolt and said yoke member adapted to continuously bias said latch bolt to projected position, said latch bolt being depressible from projected position independently of said yoke member; a fixed abutment on said case; a dogging member mounted on said latch :bolt within said case and being movable bodily with and rockable independently on said latch bolt between a dogging position engaged with said fixed abutment and non-dogging position disengaged therefrom; said spring means being engaged with said dogging member and adapted tocontinuously bias said member, from, non-doggi-n to dogging position; constraining means on said yoke member adapted to be positioned thereby to engagesaid dogging member when said latch bolt is in its projected position to constrain said dogging-member to non-dogging position; and saiddogging member being adapted to be moved by "said latch bolt to position released fromsaid constraining means by depression of said latch bolt from its said projected position.

10,.In a latch bolt mechanism, in combinationya case; a latch bolt including a'tailpiece mounted in said case for reciprocation between a projected position and a retracted position; means for retracting said latch bolt including, a yoke member reciprocally mounted in said case and being engageable with said latch bolt tailpiece to retract said latch bolt from projected position; said latch bolt and tail piece being depressible from projected position to retracted therefrom; and said spring member adapted to V continuously bias said dogging member leg in a direction to move said dogging arm from nondogging position to dogging position engaged with said fixed abutment.

11. In a latch bolt mechanism, in combination; a case; a latch bolt including a tailpiece mounted in said case for reciprocation between 'a pro-' jected position and a retracted position; means for, retracting said latch bolt including, a yoke member reciprocally mounted in said case adapted to engage said latch bolt to retract the latter from projected to retracted position; said latch bolt and tailpiece being depressible from projected position independently of said yoke member; a spring member mounted on said tailpiece between said latch bolt and the adjacent end of said yoke member adapted to continuously bias '16 said latch bolt to projected position; said case being formed with an opening therein providing an abutment surface at one side thereof; and adogging member including a leg rockably mountedon said tailpiece between said latch bolt andsaid spring member, and a dogging arm extended from said leg member and-being rockable therewith between a dogging position with said arm. projected into said case opening in engagement with said abutment surface and a non-dogging position with said arm disengaged from the abutment surface. a

12. In a latch bolt mechanism, in combination; a case; a latch bolt mounted in said case for reciprocation between latching position projected from the case and retracted position; spring means adapted to continuously bias said latch bolt to said projected position; mechanism for engaging and retracting said latch bolt from said projected position; said latch bolt being depressible from projected position independently of said retracting mechanism; a fixed abutment in said case; a dogging member mounted in said case for movements between a dogging position en gaged with said abutmentto, lock said latch bolt in projected position against depression and nondogging'position disengaged fromsaid abutment to release said latch bolt for movement to dogging position; a constraining member mounted in position to be releasably engaged by said dog-. ging member to constrain the latter member in non-dogging position when said latch bolt is in itsprojected position; and said'dogging member adapted to be engaged by said latch bolt when depressed for displacement to a position released. from said constraining member for movement of said dogging member to dogging position engaged with said fixed abutment. GOTTHARD. HAGSTROM.

.References Cited in the file r this patent UNITED STATES PATENTS Welch Apr. 1, 1952 

